Surface abrading apparatus or tools are exemplified by the use of one or more abrasive sanding members that are suitably mounted on a movable member. These apparatus have found great use in the abrading or finishing of surfaces, such as, for example, the surfaces of relatively roughly formed metal parts, etc. In use, the sanding members are forcibly applied to and moved across the surface to be finished or the work surface, whereby a smooth finish may be obtained.
However, prior attempts at finishing surfaces through abrasion do not facilitate the maintenance of a uniform sanding pressure on the work surface whereby the sanding members are all kept in continuous contact with the work surface. Furthermore, the prior art has not provided an abrading tool which aids in the control of the sanding pressure. Also, the prior art has failed to produce an abrading tool which increases the likelihood that all the sanding members simultaneously contact the work surface. A simultaneous contact will generate a multi-directional finish on the work surface minimizing the probability of creating undesirable uni-driectional striations. Finally, the prior art has not utilized an abrading tool which ensures that all the sanding members have a maximum contact with the work surface thereby decreasing the time necessary to obtain a smooth finish on the work surface.
The above-indentified application discloses an abrading tool obviating these disadvantages of the prior art. The tool comprises a rotatable support, a plurality of elongated abrasive elements and a plurality of flexible biasing springs adapted for mounting on the rotatable support. Each biasing spring is capable of forcing or biasing an associated abrasive element toward a position that is substantially perpendicular to the rotatable support. As a result, a uniform controllable sanding pressure, simultaneous work surface contact of the abrasive elements, minimization of striations on the work surface and reduction of sanding time are achieved.
Unfortunately, the abrading tool of the above-identified application has no provision for modifying the biasing force or stiffness of the flexible springs. A modification or an adjustment of the stiffness of one or more of the flexible springs would permit a change in the rate of removal of material from the work surface without any change in the speed of the rotatable support. The same feed rate and abrasive elements could also be used even though the material removal rate is changed. Finally, modifying the stiffness of an abrasive element would accomodate different work surface characteristics such as, e.g., type of material, surface roughness, etc.